1. Field of the Invention
The invention relates to a process cartridge detachably mountable to an electrophotographic image forming apparatus and an electrophotographic image forming system, and particularly to a process cartridge detachably mountable to at least two kinds of electrophotographic image forming apparatuses differing in function from each other, and an electrophotographic image forming system using the process cartridge.
The electrophotographic image forming apparatus is an apparatus for forming an image on a recording medium by the use of the electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copier, an electrophotographic printer (such as a laser beam printer or an LED printer), a facsimile apparatus and a word processor.
Also, the process cartridge refers to charging means, developing means or cleaning means and an electrophotographic photosensitive drum integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus, or at least one of charging means, developing means and cleaning means and an electrophotographic photosensitive drum integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus, or at least developing means and an electrophotographic photosensitive drum integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus.
2. Description of the Related Art
In the electrophotographic image forming apparatus using the electrophotographic image forming process, there is adopted a process-cartridge system in which an electrophotographic photosensitive member and process means for acting on the electrophotographic photosensitive member are integrally made into a cartridge, which is made detachably mountable to the main body of the electrophotographic image forming apparatus. According to this process cartridge system, the maintenance of the apparatus can be done by a user himself without resorting to a serviceman and therefore, the operability of the apparatus can be markedly improved. Therefore, this process cartridge system is widely used in the electrophotographic image forming apparatuses.
Also, in the electrophotographic image forming apparatus of the process cartridge type, as described above, the user himself interchanges the process cartridge and therefore, electrophotographic image forming apparatuses are provided with developer amount detecting means for informing the user when a developer (e.g. a toner) has been consumed. As this developer amount detecting means, there is a system for detecting any change in the capacitance among a plurality of electrodes disposed in the process cartridge to thereby detect the amount of developer.
As the constructions of these electrodes, there are an electrode-rod-detection type (a developer-remaining-amount-presence-or-absence detecting type) in which an electrode rod is disposed at a predetermined interval from a developer bearing member and the capacitance between it and the developer bearing member is detected, and an electrode-plate-detection type (a developer-remaining-amount-successively-detecting type) in which a plurality of electrode plates opposed to one another are disposed at locations into which a developer can go, and the capacitance between the electrode plates is detected.
Generally, developer amount detecting means of the above-described electrode-rod-detection type or the electrode-plate-detection type is alternatively provided in the process cartridge in accordance with the function of the main body of the image forming apparatus. Therefore, a process cartridge provided with the developer amount detecting means of the electrode-rod-detection type could be mounted only to an image forming apparatus for the electrode-rod-detection type, and a process cartridge provided with the developer amount detecting means of the electrode-plate-detection type could be mounted only to an image forming apparatus for the electrode-plate-detection type.
The present invention is a further development of the above-described related art.
It is an object of the present invention to provide a process cartridge detachably mountable to the main bodies of electrophotographic image forming apparatuses differing in function from each other, and an electrophotographic image forming system using the process cartridge.
It is another object of the present invention to provide a process cartridge capable of being mounted to the main body of an electrophotographic image forming apparatus having a function for successively detecting a remaining amount of developer (a developer-remaining-amount-successively-detecting function) and the main body of an electrophotographic image forming apparatus having a function for detecting that developer is consumed to a predetermined remaining amount (a developer-remaining-amount-presence-or-absence-detecting function), and an electrophotographic image forming system using the process cartridge.
It is another object of the present invention to provide a process cartridge detachably mountable to the main body of a first electrophotographic image forming apparatus and the main body of a second electrophotographic image forming apparatus differing in function from the first electrophotographic image forming apparatus and to provide an image forming system using the process cartridge, the process cartridge having (a) an electrophotographic photosensitive member, (b) a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive member, (c) a developer containing portion for containing therein a developer to be used to develop the electrostatic latent image by the developing roller, (d) a first electrically conductive member disposed along the lengthwise direction of the developing roller and having one end thereof exposed from a cartridge frame, the one end being electrically connected to a first main body contact provided in the main body of the first electrophotographic image forming apparatus when the process cartridge has been mounted to the main body of the first electrophotographic image forming apparatus, and producing an electrical signal for indicating that the process cartridge has been mounted to the main body of the first electrophotographic image forming apparatus, the one end being not electrically connected to the interior of the main body of the second electrophotographic image forming apparatus when the process cartridge has been mounted to the main body of the second electrophotographic image forming apparatus, and (e) a second electrically conductive member disposed along the lengthwise direction of the developing roller and electrically connected to a cartridge electrical contact exposed from the cartridge frame, the cartridge electrical contact being electrically connected to a second main body contact provided in the main body of the second electrophotographic image forming apparatus when the process cartridge has been mounted to the main body of the second electrophotographic image forming apparatus, and producing an electrical signal for the main body of the second electrophotographic image forming apparatus to successively detect the remaining amount of the developer, the cartridge electrical contact being not electrically connected to the interior of the main body of the first electrophotographic image forming apparatus when the process cartridge is mounted to the main body of the first electrophotographic image forming apparatus.
These and other objects, features and advantages of the present invention will become more fully apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.